getattr: store more info into `struct stat`
op_type_code: introduce get<>() to get a type code from static type
C++11: Use value initialization for C struct
Introduce new dynamic library loader: dl_loader
dl_loader: add load_func_ptr template function
Use std::system_error for handling system errors

 Now planet::exception_errno dropped
Reasons:
std::system_error is highly customable and functional
Preventing reinventing the wheel
Merge branch 'ltdl_to_load' into develop

* Use libltdl for loading external module
* Use std::system_error for error handling
Add some uncommited files
Merge branch 'develop'

* Change the way to load external modules
* Small fixes
* New dependency: libltdl